This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -30 |
| 3 | 435 |
| 4 | -4060 |
| 5 | 27393 |
| 6 | -142194 |
| 7 | 589875 |
| 8 | -2004600 |
| 9 | 5673571 |
| 10 | -13518806 |
| 11 | 27292965 |
| 12 | -46805540 |
| 13 | 68090965 |
| 14 | -83530946 |
| 15 | 85371335 |
| 16 | -71159652 |
| 17 | 46655060 |
| 18 | -22594964 |
| 19 | 7171160 |
| 20 | -1111968 |
| 21 | 0 |